Compositions and Methods for the Electrodeposition of Nanotwinned Copper

ABSTRACT

A copper electroplating solution comprising a copper salt, a source of halide ions, and a linear or branched polyhydroxyl. The copper electroplating solution is used to deposit copper having a high density of nanotwinned columnar copper grains on a substrate. The linear or branched polyhydroxyl may comprise a reaction product between 2,3-epoxy-1-propanol and aminic alcohol or ammonium alcohol.

FIELD OF THE INVENTION

The present invention generally relates to the electrodeposition ofnanotwinned copper and electrolytic copper plating baths for producingnanotwinned copper deposits.

BACKGROUND OF THE INVENTION

Electrochemical deposition processes are well-established in integratedcircuit fabrication. Copper lines are formed by electroplating the metalinto very thin, high-aspect-ratio trenches and vias in a methodologycommonly referred to as “damascene” processing (pre-passivationmetallization).

Copper is one of the most essential conductors in microelectronicdevices due to high ductility and conductivity. With the advancement ofmicroelectronics, there is a continual need to create smaller and denserinterconnect features. One method towards this goal is the removal ofsolder between two separate substrates that connect copper vias, pads,bumps, or pillars, which can be accomplished, for example, by process ofCu-Cu hybrid bonding.

Due to the combination of excellent mechanical properties, goodconductivity, and unique structure, nanotwinned copper has drawnattention for use in microelectronics.

In particular, the mechanical strength of metallic materials such ascopper generally increases when the size of the crystal grain is reducedto a nanoscale level. Nanotwinned copper represents ultrafine-graincopper whose grains contain a high density of layered nanoscopic twinsdivided by coherent twin boundaries. By introducing nanoscale twins intothe microstructure of copper, properties such as mechanical strength,ductility, electromigration resistivity, and hardness can be improved.

Some nanoscale levels of thin metal films can even have particularmechanical properties. As a result, it has been found that metal havingnanotwin crystalline properties can be suitable for applications ofthrough silicon via, semiconductor chip interconnect, packagingsubstrate pin through hole, metal interconnect (for example, copperinterconnect), or metal materials on substrate.

Nanotwinned copper can be achieved in several ways, including, forexample, sputtering and electrolytic deposition. One of the advantagesof sputtering is the high purity in the copper film, with the ability tocontour the preferred orientation of grains. Sputtered (111)-orientednanotwinned copper has been shown to have high thermal stability andstrength. On the other hand, direct current electrolytic plating is verycompatible with industrial mass production, and electroplatednanotwinned copper can be classified into two groups—equiaxial grainnanotwinned copper and (111)-oriented nanotwinned copper.

Crystal defects can influence mechanical, electrical, and opticalproperties of the material. Twinning may occur in a material where twoparts of a crystal structure are symmetrically related to one another.In a face-centered cubic (FCC) crystal structure, of which copper isincluded, coherent twin boundaries may be formed as (111) mirror planesfrom which the typical stacking sequence of (111) planes is reversed. Inother words, adjacent grains are mirrored across coherent twinboundaries in a layered (111)-structure. Twins grow in a layer-by-layermanner extending along a lateral (111) crystal plane where a twinthickness is on the order of nanometers, hence the name “nanotwins.”Nanotwinned copper (nt-Cu) exhibits excellent mechanical and electricalproperties and may be used in a wide variety of applications inwafer-level packaging and advanced packaging designs.

Compared to copper having conventional grain boundaries, nanotwinnedcopper possesses strong mechanical properties, including high strengthand high tensile ductility. Nanotwinned copper also demonstrates highelectrical conductivity, which may be attributable to the twin boundary,causing electron scattering that is less significant compared to a grainboundary. Furthermore, nanotwinned copper exhibits high thermalstability, which may be attributable to the twin boundary having excessenergy on the order of magnitude lower than that of a grain boundary. Inaddition, nanotwinned copper enables high copper atom diffusivity, whichis useful for copper-to-copper direct bonding. Nanotwinned copper alsoshows high resistance to electromigration, which may be a result of twinboundaries slowing down electromigration-induced atomic diffusion.Nanotwinned copper demonstrates a strong resistance to seed etch thatmay be important in fine-line redistribution layer applications.Nanotwinned copper also shows low impurity incorporation, which resultsin fewer Kirkendall voids as a result of soldered reactions with thenanotwinned copper.

In some implementations, nanotwinned copper enables direct copper-copperbonding. Such copper-copper bonding may occur at low temperatures,moderate pressures, and lower bonding forces/times. Typically, thedeposition of copper structures results in rough surfaces. In someimplementations, prior to copper-copper bonding, electrodeposition ofnanotwinned copper may be followed by an electropolishing process toachieve smooth surfaces. With the smooth surfaces, the nanotwinnedcopper structure may be used in copper-copper bonding with shorterbonding times, lower temperatures, and fewer voids.

U.S. Pat. No. 7,074,315 to Desmaison et al., the subject matter of whichis herein incorporated by reference in its entirety, describes a copperelectrolyte for depositing a matte layer of copper. The electrolyticcopper plating bath comprises at least one polyhydroxyl compoundselected from poly(1,2,3-propanetriol), poly(2,3-epoxy-1-propanol), andderivatives thereof to produce copper deposits that are matte and show auniform, slight roughness to provide, without additional pretreatment, asufficient bond of organic coatings. However, there is no suggestion asto the use of the copper electrolyte for depositing nanotwinned copper.

WO2020/092244 to Banik et al., the subject matter of which is hereinincorporated by reference in its entirety, describes a copper structurehaving a high density of nanotwinned copper deposited on a substrate.Banik does not describe the particular electrolytic copper plating bathbut instead describes electroplating conditions, including applying apulsed current waveform that alternates between constant current and nocurrent, where the duration of no current being applied is substantiallygreater than a duration of a constant current being applied.

U.S. Pat. No. 10,566,314 to Yang, the subject matter of which is hereinincorporated by reference in its entirety, describes how the optimalcopper grain structure for Cu-Cu metal to metal bonding is columnargrain microstructure. The copper grain microstructure plated by thedisclosed suppressor-only system produces a columnar grain structure asa result of plating nanotwinned copper. While columnar grains arementioned, there is no mention of (111) copper grain structure ofnanotwinning copper.

Thus, there remains a need in the art for an improved electrolyticcopper solution for producing nanotwinned copper deposits. In addition,there remains a need in the art for an improved electrolytic coppersolution that can deposit nanotwinned copper in (111) orientation andwith a high percentage of nanotwinning.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved copperelectroplating solution.

It is another object of the present invention to provide a copperelectroplating solution that is capable of producing nanotwinned copperin the deposit.

It is still another object of the present invention to providenanotwinned copper in (111) orientation.

It is yet another object of the present invention to provide a copperdeposit having a high density of nanotwinning.

To that end, in one embodiment, the present invention generally relatesto a copper electroplating solution used to produce nanotwinned coppercomprises typically:

A) a copper salt;

B) a source of halide ions; and

C) a linear or branched polyhydroxyl.

In another embodiment, the present invention also relates generally to amethod of using the copper electroplating solution described herein toproduce a copper deposit having a high density of nanotwinning.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 depicts an SEM (30 μm width at 10K magnification) of a copperdeposit produced in accordance with Comparative Example 1.

FIG. 2 depicts an SEM (30 μm width at 10K magnification) of a copperdeposit produced in accordance with Example 2.

FIG. 3 depicts an SEM (30 μm width at 10K magnification) of a copperdeposit produced in accordance with Comparative Example 3.

FIG. 4 depicts an SEM (60 82 m width at 5K magnification) of a copperdeposit produced in accordance with Comparative Example 4.

FIG. 5 depicts an SEM (75 μm width at 4K magnification) of a copperdeposit produced in accordance with Example 5.

FIG. 6 depicts an SEM (50 μm width at 6K magnification) of a copperdeposit produced in accordance with Example 6.

FIG. 7 depicts an SEM (30 μm width at 10K magnification) of a copperdeposit produced in accordance with Example 7.

FIG. 8 depicts the grain orientation of the copper deposit produced inaccordance with Example 7.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventors of the present invention have discovered thatelectrodeposition of high density of nanotwin copper in (111)orientation can enable smaller and denser interconnect features betweentwo separate substrates used to connect copper vias, pads, bumps,pillars, etc. via Cu-Cu hybrid bonding.

As used herein, “a,” “an,” and “the” refer to both singular and pluralreferents unless the context clearly dictates otherwise.

As used herein, the term “about” refers to a measurable value such as aparameter, an amount, a temporal duration, and the like and is meant toinclude variations of +/−15% or less, preferably variations of +/−10% orless, more preferably variations of +/−5% or less, even more preferablyvariations of +/−1% or less, and still more preferably variations of+/−0.1% or less of and from the particularly recited value, in so far assuch variations are appropriate to perform in the invention describedherein. Furthermore, it is also to be understood that the value to whichthe modifier “about” refers is itself specifically disclosed herein.

As used herein, spatially relative terms, such as “beneath,” “below,”“lower,” “above,” “upper” and the like, are used for ease of descriptionto describe one element or feature's relationship to another element(s)or feature(s) as illustrated in the figures. It is further understoodthat the terms “front” and “back” are not intended to be limiting andare intended to be interchangeable where appropriate.

As used herein, the terms “comprises” and/or “comprising,” specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

As used herein, the term “substantially free” or “essentially free” ifnot otherwise defined herein for a particular element or compound meansthat a given element or compound is not detectable by ordinaryanalytical means that are well known to those skilled in the art ofmetal plating for bath analysis. Such methods typically include atomicabsorption spectrometry, titration, UV-Vis analysis, secondary ion massspectrometry, and other commonly available analytically techniques.

All amounts are percent by weight unless otherwise noted. All numericalranges are inclusive and combinable in any order except where it islogical that such numerical ranges are constrained to add up to 100%.

The terms “plating” and “deposit” or “deposition” are usedinterchangeably throughout this specification. The terms “composition”and “bath” and “solution” are used interchangeably throughout thisspecification. The term “alkyl,” unless otherwise described in thespecification as having substituent groups, means an organic chemicalgroup composed of only carbon and hydrogen and having a general formula:C_(n)H_(2n+1). The term “average” is equivalent to the mean value of asample. All amounts are percent by weight unless otherwise noted. Allnumerical ranges are inclusive and combinable in any order except whereit is logical that such numerical ranges are constrained to add up to100%.

In one embodiment, the present invention generally relates to theelectrodeposition of nanotwinned copper, and the copper electroplatingsolution used to produce nanotwinned copper comprises typically:

A) a copper salt;

B) a source of halide ions; and

C) a linear or branched polyhydroxyl.

In a preferred embodiment, the copper salt comprises copper sulfate.Other copper salts usable in the composition include copper methanesulfonate, copper pyrophosphate, copper propanesulfonate, and othersimilar compounds. The concentration of copper sulfate in theelectroplating solution is generally in the range of about 1-100 g/L,more preferably in the range of about 20 to about 80 g/L, mostpreferably within the range of about 40 to about 60 g/L.

The halide ions may act as bridges to assist adsorption of certainorganic additives onto a substrate surface. Halide ions include, but arenot limited to, chloride ions, bromide ions, iodide ions, andcombinations thereof. In one embodiment, the halide ions comprisechloride ions. The concentration of chloride ions in the electroplatingsolution is generally within the range of about 1-150 mg/L, morepreferably about 30-120 mg/L, most preferably about 45-75 mg/L.

The linear or branched polyhydroxyl generally has a molecular weight ofabout 200 to about 20,000 g/mol, more preferably about 500 to about5,000 g/mol, most preferably about 1,000 to about 3,000 g/mol. In apreferred embodiment, the linear or branched polyhydroxyl comprisespoly(2,3-epoxy-1-propanol). In one embodiment, the concentration of thelinear or branched polyhydroxyl is within the range of about 1 to about10,000 mg/L, more preferably about 10 to about 1,000 mg/L, mostpreferably about 50 to about 600 mg/L.

In addition, the electroplating composition may contain an acid tocontrol the conductivity of the plating bath, and suitable acids includesulfuric acid and methane sulfonic acid. In one embodiment, the acid issulfuric acid. The concentration of acid in the electroplating solutionis generally within the range of about 0 to 240 g/L, more preferablywithin the range of about 10 to about 180 g/L, most preferably withinthe range of about 80 to about 140 g/L.

The inventors have also surprisingly found that reacting aminic alcoholsor ammonium alcohols with 2,3-epoxy-1-propanol can improve theproperties of the nanotwinned copper. These polyhydroxyl compounds thatare initiated by a core containing a nitrogen species can increase thecolumnar nanotwinned copper density and help initiate the nanotwinnedcopper more quickly than poly(2,3-epoxy-1-propanol).

Examples of these aminic alcohols include, but are not limited to,ethanolamine, diethanolamine, triethanolamine, propanolamine,isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyl diethanolamine, N-propyl diethanolamine, methylmonoethanolamine, N,N-dimethyl ethanolamine, N,N-diethyl ethanolamine,N-propyl monoethanolamine, N-propyl diethanolamine, N-butylethanolamine, N-butyl diethanolamine, N,N-dibutyl ethanolamine, hydroxyethyl morpholine, 2-piperidino ethanol, diethanol isopropanolamine,N-(2-hydroxyethyl) pyrrolidine, and combinations of the foregoing.

In addition, an aminic alcohol can convert to an ammonium salt byquatemizing the nitrogen, for example, by means of a methylating agentsuch as dimethylsulfate.

Examples of ammonium alcohols include, but are not limited to, cholinechloride, b-methyleholine chloride, bis(2-hydroxyethyl)dimethylammoniumchloride, tris(2-hydroxyethyl)methylammonium chloride, carnitinechloride, (2-hydroxyethyl)dimethyl(3-sulfopropyl)ammonium chloride, andcombinations of the foregoing.

In reacting an aminic or ammonium alcohol with 2,3-epoxy-1-propanol, themolar ratio of the amine to the 2,3-epoxy-1-propanol is generally in therange of about 0.01 to 0.50, more preferably in the range of 0.01 to0.20, and more preferably in the range of 0.01 to 0.10.

The inventors have also found that the introduction of other organicelectroplating compounds can disrupt the ability of the polyhydroxylmaterial to produce nanotwinned copper. These prohibitive compoundsinclude accelerators, brighteners, carriers, wetters, and/or levelers.Thus, in a preferred embodiment, the electroplating solution is at leastsubstantially free of any accelerator, brightener, carrier, wetter,and/or leveler or any compound that can function as an accelerator,brightener, carrier, wetter, and/or leveler. By “substantially free of”what is meant is that the electroplating solution contains less than 20ppm, more preferably less than about 10 ppm, and most preferably lessthan about 3 ppm of any compound that can function as an accelerator,brightener, carrier, wetter, and/or leveler.

In one preferred embodiment, the copper electroplating composition ofthe present invention comprises:

-   -   A) about 40 to about 60 g/L copper ions;    -   B) about 80 to about 140 g/L sulfuric acid;    -   C) about 30 to about 120 mg/L chloride ions;    -   D) about 300 to about 500 mg/L of a linear or branched        polyhydroxyl, wherein the polymer may or may not contain a        nitrogen-containing species.

In another preferred embodiment, the present invention consistsessentially of a copper electroplating composition capable ofelectrodepositing copper having a high density of nanotwinned copper,the electroplating composition consisting essentially of:

A) about 40 to about 60 g/L copper ions;

B) about 80 to about 140 g/L sulfuric acid;

C) about 30 to about 120 mg/L chloride ions;

D) about 300 to about 500 mg/L of a linear or branched polyhydroxylwherein the polymer may or may not contain a nitrogen-containingspecies.

By “consisting essentially of,” what is meant is that the composition isfree of any additive that would have a detrimental effect on the abilityof the composition to produce a nanotwinned copper deposit.

The present invention also relates generally to a method ofelectroplating nanotwinned copper on a substrate, the method comprisingthe steps of:

A) providing the substrate, at least one anode, and the copper platingbath described above;

B) contacting the surface of the substrate and the at least one anode,respectively, with the copper bath; and

C) applying an electric voltage between the surface of the workpiece andthe at least one anode such that cathodic polarity is imposed upon thesubstrate relative to the at least one anode;

wherein a copper structure having a high density of nanotwinning isdeposited on the substrate.

In some embodiments, the nanotwinned copper structures have a pluralityof (111) crystal grain structures. Furthermore, to ensure the success ofthis method, which requires elevated temperatures and pressures, it isgenerally preferred to generate electroplated copper in (111)orientation with >90% nanotwinned columnar copper (nt-Cu) grains. Whilenot being held to a particular theory, it is hypothesized that when thetwo nanotwinned copper substrates come into contact and are exposed tothe necessary temperatures and pressures, the nanotwinned copper growthwill extend between the boundaries of the copper substrate, forming aCu-Cu bond that extends across the interface.

The current density is generally in the range of about 0.01 to about 50ASD, more preferably about 0.5 to about 20 ASD, most preferably about 1to about 10 ASD. In addition, the electroplating solution is preferablyagitated, and the electroplating solution is generally mixed at about 1to about 2,500 rpm, more preferably about 10 to about 1,200 rpm, mostpreferably about 50 to about 400 rpm.

The anode is preferably an insoluble anode.

The copper is electrodeposited for some time to plate copper to athickness of about 0.1 to about 1,000 μm, more preferably about 0.3 toabout 200 μm, most preferably about 1 to about 100 μm.

Substrates that can be plated with the copper electroplating solutioninclude, for example, pillars, pads, lines, and vias.

The presence of nanotwinned grain structures can be observed using anysuitable microscopy technique, such as an electron microscopy technique.The amount of nanotwinned grain structure in the copper deposit ispreferably greater than about 80%, more preferably greater than about90% nanotwinned columnar copper grains, which is estimated based on SEMcross-sections.

As set forth in the examples below, nanotwinned copper structures may becharacterized by a plurality of (111)-oriented crystal copper grainscontaining a majority of nanotwins. In some implementations, theplurality of (111)-oriented crystal copper grains contain a high densityof nanotwins. As used herein, a “high density of nanotwins” may refer tocopper structures having greater than about 80% nanotwinning, and evengreater than about 90% nanotwinning as observed using suitablemicroscopy techniques.

The crystal orientation of the crystal copper grains may becharacterized using a suitable technique such as electron backscatterdiffraction (EBSD) analysis. In some implementations, crystalorientation maps may be displayed in inverse pole figure (IPF) maps. Inaccordance with the present invention, it is preferably that thenanotwinned copper structures contain primarily (111)-oriented grains.

COMPARATIVE EXAMPLE 1

A copper electrolytic composition was prepared to contain a solution of50 gIL copper(II) ion, 100 g/L sulfuric acid, 50 mg/L chloride ion, and400 mg/L polyethylene glycol (PEG) and disposed of in a plating cell. Ablanket PVD copper substrate was submerged into the plating cell at 25°C. Agitation was set to 300 rpm, and a current density of 6 ASD wasapplied for 500 s in order to plate a 10 μm film of copper.

As depicted in FIG. 1, the SEM cross-section reveals the absence ofnanotwinned copper in the plated film of copper.

EXAMPLE 2

The same bath and substrate, as described in Comparative Example 1, wasprepared; however, the PEG was replaced with 400 mg/L ofpoly(2,3-epoxy-1-propanol) and electroplated under the same platingconditions. The results showed a majority of nanotwinned copper.

As depicted in FIG. 2, the SEM cross-section shows a majority ofnanotwinned copper in the plated film. The grains are highly columnarand have a high density of grown-in nanotwins.

COMPARATIVE EXAMPLE 3

The same bath and substrate, as described in Example 2 was prepared,except that 1 mg/L of bis(sodium sulfopropyl)disulfide (SPS)(brightening agent) was added to the solution and electroplated underthe same plating conditions. The results showed that the addition of aconventional brightening agent to the composition resulted in a completeloss of nanotwinned copper in the plated film, as seen in FIG. 3.

COMPARATIVE EXAMPLE 4

The same bath and substrate, as described in Example 2, was prepared.However, 5 mg/L of a cationic nitrogen leveler was added to the solutionand electroplated under the same plating conditions. As seen in FIG. 4,the addition of a leveler to the plating composition also resulted in acomplete loss of nanotwinned copper.

EXAMPLE 5

The same bath, as described in Example 2, was prepared, and a substrate70 μm wide was plated at 6 ASD to create a 40 μm tall pillar. Theresults show a high density of nanotwinned copper, as depicted in FIG.5.

EXAMPLE 6

The same bath, as described in Example 5, was prepared, and a substratecontaining a via was plated. The results show a high majority ofnanotwinned copper, as depicted in FIG. 6.

EXAMPLE 7

An additive can be prepared by reacting an aminic or ammonium alcoholwith 2,3-epoxy-1-propanol. The general reaction procedure is as follows:

A boron trifluoride etherate (5 mmol) solution in methanol was addeddropwise to a solution of 2,3-epoxy-1-propanol (2 mol) andN-methyldiethanolamine (0.2 mo1) in a 1L round bottom flask equippedwith a thermometer, reflux condenser, and magnetic stirrer. Thetemperature was allowed to increase freely during exotherm and heated atits maximum temperature for 30 minutes. The reaction was then allowed tocool to less than 100° C., where water was added to make a 20% w/wsolution that continued to stir for 4 hours. This solution was thenfiltered and used as-is.

The bath, as described in Example 2, was plated using the above-preparedadditive.

The results show faster nanotwin initiation from the copper seed. Also,a denser array of nanotwinned columnar growth is observed, as depictedin FIG. 7. The grain structure of the copper deposit is depicted in FIG.8 as being dominated by a (111) grain orientation.

As can be seen from the Examples and Comparative Examples, the copperelectroplating composition of the invention is capable of depositing aplated copper structure that comprises a high density of nanotwinnedcolumnar copper grains.

Finally, it should also be understood that the following claims areintended to cover all of the generic and specific features of theinvention described herein and all statements of the scope of theinvention that, as a matter of language might fall therebetween.

What is claimed is:
 1. A copper electroplating solution comprising: a) acopper salt; a source of halide ions; and c) a linear or branchedpolyhydroxyl, wherein the linear or branched polyhydroxyl comprises areaction product between 2,3-epoxy-1-propanol and an ii alcohol orammonium alcohol, wherein the copper electroplating solution isconfigured for of depositing nanotwinned copper on a substrate.
 2. Thecopper electroplating solution according to claim 1, wherein the coppersalt is copper sulfate.
 3. The copper electroplating solution accordingto claim 1, further comprising an acid, wherein the acid comprisessulfuric acid or methane sulfonic acid.
 4. (Currently amended The copperelectroplating solution according to claim 15, wherein the linear orbranched polyhydroxyl comprises polymerized 2,3-epoxy-1-propanol.
 5. Thecopper electroplating solution according to claim 16, wherein the linearor branched polyhydroxyl comprises a reaction product between2,3-epoxy-1-propanol and atomic alcohol or ammonium alcohol.
 6. Thecopper electroplating solution according to claim 15, wherein the linearor branched polyhydroxyl comprises at least one nitrogen atom.
 7. Thecopper electroplating solution according to claim 1, wherein the aminicalcohol or the ammonium alcohol is selected from the group consisting ofethanolamine, diethanolamine, triethanolamine, propanolamine,isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, N-ethyl diethanolamine, N-propyl diethanolamine, methylmonoethanolamine, N,N-dimethyl ethanolamine, N-diethyl ethanolamine,N-propyl monoethanolamine, N-propyl diethanolamine, N-butylethanolamine, N-butyl diethanolamine, N,N-dibutyl ethanolamine, hydroxyethyl morpholine, 2-piperidino ethanol, diethanol isopropanolamine,N-(2-hydroxyethyl) pyrrolidine, choline chloride, b-methylcholinechloride, Bis(2-hydroxyethyl)dimethylammonium chloride,trs(2-hydroxyethyl)methylammonium chloride, carnitine chloride,(2-hydroxyethyl)dimethyl(3-sulfopropyl)ammonium chloride, andcombinations of the foregoing.
 8. The copper electroplating solutionaccording to claim 4, wherein the copper electroplating solutioncomprises: a. about 40 to about 60 g/L copper ions; b. about 80 to about140 g/L sulfuric acid; c. about 30 to about 120 mg/L chloride ions; d.about 300 to about 600 mg/L linear or branched polyhydroxyl; wherein thepolyhydroxyl comprises polymerized 2,3-epoxy-1-propanol directly bondedto a nitrogen-containing species.
 9. The copper electroplating solutionaccording to claim 1, wherein the copper electroplating solution is atleast substantially free of any other accelerator, brightener, carrier,wetter. or leveler or any additional compound that can function as anaccelerator. brightener, carrier, wetter, or leveler.
 10. A method ofelectrodepositing copper on a substrate, the method comprising the stepsof: a. contacting a surface of the substrate and at least one anode withthe copper electroplating solution of claim 1; and b. applying anelectric voltage between the surface of the substrate and the at leastone anode such that cathodic polarity is imposed upon the substraterelative to the at least one anode; wherein a copper deposit having ahigh density of nanotwinned columnar copper grains is deposited on thesubstrate.
 11. The method according to claim 1 wherein the nanotwinnedcopper deposit is in a (111) orientation.
 12. The method according toclaim 10, wherein the copper deposit Comprises greater than 80%nanotwinned columnar copper grains.
 13. The method according to claim12, wherein the copper deposit comprises greater than 90% nanotwinnedcolumnar copper grains.
 14. The method according to claim 10, whereinthe substrate comprises one or more features selected from the groupconsisting of pillars, pads, lines, via and combinations of one or moreof the foregoing.
 15. A copper electroplating solution comprising: a) acopper salt; b) a source of halide ions; and c) a linear or branchedpolyhydroxyl, wherein the copper electroplating solution is configuredfor depositing nanotwinned copper on a substrate, and wherein the copperelectroplating solution is at least substantially free of any otheraccelerator, brightener, carrier, wetter, or leveler or any additionalcompound that can function as an accelerator, brightener, carrier,wetter, or leveler.
 16. A copper electroplating solution consistingessentially of: a) a copper salt; b) a source of halide ions; and c) alinear or branched polyhydroxyl; and d) an acid wherein the copperelectroplating solution is configured for depositing nanotwinned copperon a substrate.
 17. The copper electroplating solution according toclaim 16, wherein the copper electroplating solution is at leastsubstantially free of any other accelerator, brightener, carrier,wetter, or leveler or any additional compound that can function as anaccelerator, brightener, carrier, wetter, or leveler,
 18. The copperelectroplating solution of claim 1, wherein in reacting the aminicammonium alcohol with 2,3-epoxy-1-propanol, the molar ratio of amine tothe 2,3-epoxy-1-propanol is in the range of 0.01 to 0.5.
 19. The copperelectroplating solution of claim 18, wherein in reacting the aminicammonium alcohol with 2,3-epoxy-1-propanol, the molar ratio of amine tothe 2,3-epoxy-1-propanol is in the range of 0.01 to 0.2.